Wet wipes and methods for making same

ABSTRACT

Wet wipes formed from a fibrous structure and a liquid composition that exhibit novel properties are provided.

CROSS REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit of U.S. Provisional Application No.61/393,098, filed Oct. 14, 2010.

FIELD OF THE INVENTION

The present invention relates to wet wipes and more particularly to wetwipes that comprise a fibrous structure and a liquid composition thatexhibit novel properties.

BACKGROUND OF THE INVENTION

Various fibrous structures have been used in the past as substrates forwet wipes. For example, fibrous structures comprising a mixture of pulpand regenerated cellulose fibers, such as rayon and/or lyocell, with orwithout binding fibers, such as polypropylene/polyester bicomponentfibers, are known to be used as substrates for wet wipes. Further,fibrous structures comprising 100% pulp fibers are also known to be usedas substrates for wet wipes. Still further yet, fibrous structurescomprising 100% polypropylene fibers are known to be used as substratesfor wet wipes.

One important property that consumers desire is that wet wipes must bestrong enough to maintain integrity during use, which is oftentimes 28days or greater from the time the wet wipe is produced. In order tomaintain integrity during use, known wet wipes utilize varioustechnologies. For example, some wet wipes achieve strength by usingthermoplastic polymers, such as polypropylene, to form thefilaments/fibers of their fibrous structures and then optionally,thermal bonding the fibrous structures. Others achieve strength by theprocess by which they are made, for example, hydroentangling(spunlacing). Still others achieve strength by adding a polymeric binderto the fibrous structures, for example an acid-insoluble, alkali-solublepolycarboxylic acid binder and/or an ion-triggerable polymeric bindersand/or temperature-sensitive binders and/or pH sensitive binders and/orwater-soluble binder such as polyvinyl alcohol that are typicallyapplied to the fibrous structure prior to application of any liquidcomposition. In the case of wet wipes that comprise a 100% pulp fiberfibrous structure, strength has been achieved by employing a permanentwet strength agent, such as Kymene®, which is commercially availablefrom Ashland Inc. and/or Parez® 631, which is commercially availablefrom Kemira Chemicals Inc., during the fibrous structure making process,which can be a wet-laid papermaking process.

Another important property that consumers desire is that the wet wipesneed to be dispersible in order for the consumers to dispose of byflushing in a toilet and into a sewer system, such as a publics sewersystem, and/or a septic system without creating clogging issues. Inorder to achieve dispersibility, known wet wipes have utilized wetstrength technologies such as those described above that may betriggered by some condition that causes the wet wipe to break apart intosmaller pieces. In addition some wet wipes have used mechanicalweakening to aid in dispersibility of the wet wipe.

The challenge that has haunted formulators in the past is balancing thein-use wet strength requirements with the dispersibility requirements.For example, one can achieve a high in-use wet strength in a wet wipe,but the wet wipe may exhibit little or no dispersibility. In anotherexample, a wet wipe may exhibit low in-use wet strength, but the wetwipe may disperse readily. In one example, a wet wipe may exhibit a highinitial wet strength that deteriorates over time prior to use as aresult of the wet wipe comprising its liquid composition. For example,the wet wipe comprising its liquid composition may at the time ofpackaging exhibit sufficient wet strength, but after sitting in thepackage for sometime, for example 28 days or longer, the wet strength ofthe wet wipe has deteriorated to an unacceptable level for consumers.

In light of the foregoing, consumers desire a wet wipe that exhibitssufficient wet strength during use, even 28 days after the wet wipe hasbeen produced, and a dispersibility that is better than known andexisting wet wipes.

Accordingly, there is a need for a wet wipe that exhibits sufficienttotal wet tensile strength during use and an improved dispersibility.

SUMMARY OF THE INVENTION

The present invention fulfills the need described above by providing awet wipe that exhibits a total wet tensile strength that is acceptableto consumers during use and an improved dispersibility compared to knownwet wipes.

It has unexpectedly been found that a wet wipe that combines a temporarywet strength agent within a fibrous structure, which comprises a liquidcomposition that exhibits a pH of less than 4.55 after being extractedfrom the fibrous structure, provides sufficient total wet tensile duringuse and improved dispersibility compared to known wet wipes.

In one example of the present invention, a wet wipe comprising a fibrousstructure comprising a liquid composition, wherein the liquidcomposition after extraction from the fibrous structure exhibits a pH ofless than 4.55 as measured according to the pH Test Method describedherein, is provided.

In another example of the present invention, a wet wipe comprising afibrous structure comprising a liquid composition, wherein the fibrousstructure comprises a temporary wet strength agent, is provided.

In still another example of the present invention, a wet wipe comprisinga fibrous structure comprising a liquid composition, wherein the fibrousstructure comprises a temporary wet strength agent and the liquidcomposition after extraction from the fibrous structure exhibits a pH ofless than 4.55 as measured according to the pH Test Method describedherein, is provided.

In even another example of the present invention, a wet wipe comprisinga fibrous structure comprising greater than 85% by weight of the fibrousstructure on a dry basis of pulp fibers, a temporary wet strength agent,and a liquid composition, is provided.

In even another example of the present invention, a wet wipe comprisinga fibrous structure comprising greater than 85% by weight of the fibrousstructure on a dry basis of pulp fibers and a liquid composition thatexhibits a pH of less than 4.55 as measured according to the pH TestMethod described herein, is provided.

In even still another example of the present invention, a wet wipecomprising a fibrous structure comprising a surface pattern imparted tothe fibrous structure during the fibrous structure making process and aliquid composition, is provided.

In yet another example of the present invention, a method for making awet wipe comprising the steps of:

-   -   a. providing a fibrous structure; and    -   b. contacting the fibrous structure with a liquid composition        such that the pH of the liquid composition after being extracted        from the fibrous structure is less than 4.55 as measured        according to the pH Test Method to produce a wet wipe, is        provided.

In still yet another example of the present invention, a method formaking a wet wipe comprising the steps of:

-   -   a. providing a fibrous slurry comprising a plurality of fibers        and a temporary wet strength agent;    -   b. depositing the fibrous slurry onto a forming wire to form an        embryonic web;    -   c. transferring the embryonic web to a patterned belt to impart        a surface pattern to the embryonic web;    -   d. drying the embryonic web to form a fibrous structure; and    -   e. contacting the fibrous structure with a liquid composition to        form a wet wipe, is provided.

Accordingly, the present invention provides novel wet wipes comprising afibrous structure and a liquid composition and methods for making same.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of an example of a fibrousstructure in accordance with the present invention;

FIG. 2 is a cross-sectional view of FIG. 1 taken along line 2-2;

FIG. 3 is a schematic representation of another example of a fibrousstructure in accordance with the present invention;

FIG. 4 is a cross-sectional view of FIG. 3 taken along line 4-4;

FIG. 5 is a schematic representation of an example of a fibrousstructure in accordance with the present invention; and

FIG. 6 is a cross-sectional view of FIG. 5 taken along line 6-6.

DETAILED DESCRIPTION OF THE INVENTION Definitions

“Fibrous structure” as used herein means a structure that comprises oneor more filaments and/or fibers. In one example, a fibrous structureaccording to the present invention means an orderly arrangement offilaments and/or fibers within a structure in order to perform afunction. Non-limiting examples of fibrous structure of the presentinvention include paper, fabrics (including woven, knitted, andnon-woven), and absorbent pads (for example for diapers or femininehygiene products).

Non-limiting examples of processes for making fibrous structures includeknown wet-laid papermaking processes, air-laid papermaking processes,and other nonwoven making processes such as meltblowing, spunbonding,and carding. Such wet-laid and/or air-laid papermaking processestypically include steps of preparing a fiber composition in the form ofa suspension in a medium, either wet, more specifically aqueous medium,or dry, more specifically gaseous, i.e. with air as medium. The aqueousmedium used for wet-laid processes is oftentimes referred to as a fiberslurry. The fibrous slurry is then used to deposit a plurality of fibersonto a forming wire or belt such that an embryonic fibrous structure isformed, after which drying and/or bonding the fibers together results ina fibrous structure. Further processing the fibrous structure may becarried out such that a wet wipe is formed.

The fibrous structures of the present invention may be homogeneous ormay be layered. If layered, the fibrous structures may comprise at leasttwo and/or at least three and/or at least four and/or at least fivelayers.

The fibrous structures of the present invention may be co-formed fibrousstructures.

“Co-formed fibrous structure” as used herein means that the fibrousstructure comprises a mixture of at least two different materialswherein at least one of the materials comprises a filament, such as apolypropylene filament, and at least one other material, different fromthe first material, comprises a solid additive, such as a fiber and/or aparticulate. In one example, a co-formed fibrous structure comprisessolid additives, such as fibers, such as wood pulp fibers, andfilaments, such as polypropylene filaments.

“Solid additive” as used herein means a fiber and/or a particulate.

“Particulate” as used herein means a granular substance or powder.

“Fiber” and/or “Filament” as used herein means an elongate particulatehaving an apparent length greatly exceeding its apparent width, i.e. alength to diameter ratio of at least about 10. In one example, a “fiber”is an elongate particulate as described above that exhibits a length ofless than 5.08 cm (2 in.) and a “filament” is an elongate particulate asdescribed above that exhibits a length of greater than or equal to 5.08cm (2 in.).

Fibers are typically considered discontinuous in nature. Non-limitingexamples of fibers include wood pulp fibers and synthetic staple fiberssuch as polyester fibers.

Filaments are typically considered continuous or substantiallycontinuous in nature. Filaments are relatively longer than fibers.Non-limiting examples of filaments include meltblown and/or spunbondfilaments. Non-limiting examples of materials that can be spun intofilaments include natural polymers, such as starch, starch derivatives,cellulose and cellulose derivatives, hemicellulose, hemicellulosederivatives, and synthetic polymers including, but not limited topolyvinyl alcohol filaments and/or polyvinyl alcohol derivativefilaments, and thermoplastic polymer filaments, such as polyesters,nylons, polyolefins such as polypropylene filaments, polyethylenefilaments, and biodegradable or compostable thermoplastic fibers such aspolylactic acid filaments, polyhydroxyalkanoate filaments andpolycaprolactone filaments. The filaments may be monocomponent ormulticomponent, such as bicomponent filaments.

In one example of the present invention, “fiber” refers to papermakingfibers. Papermaking fibers useful in the present invention includecellulosic fibers commonly known as wood pulp fibers. Applicable woodpulps include chemical pulps, such as Kraft, sulfite, and sulfate pulps,as well as mechanical pulps including, for example, groundwood,thermomechanical pulp and chemically modified thermomechanical pulp.Chemical pulps, however, may be preferred since they impart a superiortactile sense of softness to tissue sheets made therefrom. Pulps derivedfrom both deciduous trees (hereinafter, also referred to as “hardwood”)and coniferous trees (hereinafter, also referred to as “softwood”) maybe utilized. The hardwood and softwood fibers can be blended, oralternatively, can be deposited in layers to provide a stratified web.U.S. Pat. No. 4,300,981 and U.S. Pat. No. 3,994,771 are incorporatedherein by reference for the purpose of disclosing layering of hardwoodand softwood fibers. Also applicable to the present invention are fibersderived from recycled paper, which may contain any or all of the abovecategories as well as other non-fibrous materials such as fillers andadhesives used to facilitate the original papermaking. Non-limitingexamples of suitable hardwood pulp fibers include eucalyptus and acacia.Non-limiting examples of suitable softwood pulp fibers include SouthernSoftwood Kraft (SSK) and Northern Softwood Kraft (NSK).

“Hardwood pulp fiber” as used herein means pulp fibers obtained fromdeciduous trees. Non-limiting examples of deciduous trees includeNorthern hardwood trees and tropical hardwood trees. Non-limitingexamples of hardwood pulp fibers include hardwood pulp fibers obtainedfrom a fiber source selected from the group consisting of Acacia,Eucalyptus, Maple, Oak, Aspen, Birch, Cottonwood, Alder, Ash, Cherry,Elm, Hickory, Poplar, Gum, Walnut, Locust, Sycamore, Beech, Catalpa,Sassafras, Gmelina, Albizia, Anthocephalus, Magnolia, and mixturesthereof. In one example, the hardwood pulp fiber of the presentinvention is obtained from Eucalyptus.

“Tropical hardwood pulp fiber” as used herein means pulp fibers obtainedfrom a tropical hardwood tree. Non-limiting examples of tropicalhardwood trees include Eucalyptus trees and/or Acacia trees.

In addition to the various wood pulp fibers, other cellulosic fiberssuch as cotton linters, rayon, lyocell and bagasse can be used in thisinvention. Other sources of cellulose in the form of fibers or capableof being spun into fibers include grasses and grain sources.

In addition, trichomes such as from “lamb's ear” plants and seed hairscan also be utilized in the fibrous structures of the present invention.

In one example, the fibrous structure may comprise 100% by weight on adry fiber basis of softwood fibers, such as NSK fibers. In anotherexample, the fibrous structure may comprise a mixture of softwoodfibers, such as NSK fibers, and hardwood fibers, such as Eucalyptusfibers. In still another example, the fibrous structure may compriseless than 100% and/or less than 90% and/or less than 80% and/or to about70% by weight on a dry fiber basis of softwood fibers, such as NSKfibers, and greater than 0% and/or greater than 10% and/or greater than20% and/or to about 30% by weight on a dry fiber basis of hardwoodfibers, such as Eucalyptus fibers.

In one example, the fibrous structure may comprise greater than 50%and/or 70% or greater by weight on a dry basis of softwood fibers andless than 50% and/or 30% or less by weight on a dry basis of hardwoodfibers.

In still another example, the fibrous structure may comprise greaterthan 0% and/or greater than 5% and/or greater than 10% and/or greaterthan 20% and/or greater than 30% and/or to about 50% by weight on a dryfiber basis of fibers, such as pulp fibers, that exhibit a mean fiberlength of from less than 1 mm and/or less than 0.9 mm and/or less than0.8 mm and/or to about 0.5 mm and/or to about 0.6 mm and/or to about 0.7mm.

“Wet wipe” as used herein means a fibrous structure that containsgreater than 20% and/or greater than 40% and/or greater than 50% and/orgreater than 75% by weight of the wet wipe of a liquid composition. Inone example, the fibrous structure of the present invention comprises a% saturation of greater than 50% and/or greater than 75% and/or greaterthan 100% and/or greater than 125% and/or greater than 150% and/or toabout 1000% and/or to about 500% and/or to about 400% and/or to about300% and/or to about 250% and/or to about 200%.

The liquid composition may be added to the fibrous structure to form awet wipe prior to and/or after packaging and/or prior to and/or afterfolding, if any, and/or prior to and/or after any post processingoperation, such as embossing, tuft generating, printing, combining withother fibrous structure plies and mixtures thereof. The wet wipe istypically packaged in a moisture impervious container and/or wrapper.The wet wipe may be in the form of one or more individual sheets, suchas a stack of sheets, which may be interleaved. In another example, thewet wipes of the present invention may be in the form of wet wipe rolls.Such wet wipe rolls may comprise a plurality of connected, butperforated sheets of fibrous structure, that are separably dispensablefrom adjacent sheets.

The fibrous structure, as described above, may be utilized to form a wetwipe. “Wet wipe” may be a general term to describe a piece of material,generally fibrous structure, used in cleansing hard surfaces, food,inanimate objects, toys and body parts. In particular, many currentlyavailable wet wipes may be intended for the cleansing of the perianalarea after defecation. Other wet wipes may be available for thecleansing of the face or other body parts. Multiple wipes may beattached together by any suitable method to form a mitt.

The fibrous structure from which a wet wipe is made should be strongenough to resist tearing during normal use, yet still provide softnessto the user's skin, such as a child's tender skin. Additionally, thefibrous structure should be at least capable of retaining its form forthe duration of the user's cleansing experience.

Wet wipes may be generally of sufficient dimension to allow forconvenient handling. Typically, the wipe may be cut and/or folded tosuch dimensions as part of the manufacturing process. In some instances,the wipe may be cut into individual portions so as to provide separatewipes which are often stacked and interleaved in consumer packaging. Inother embodiments, the wipes may be in a web form where the web has beenslit and folded to a predetermined width and provided with means (e.g.,perforations) to allow individual wipes to be separated from the web bya user. Suitably, an individual wipe may have a length between about 100mm and about 250 mm and a width between about 140 mm and about 250 mm.In one embodiment, the wipe may be about 200 mm long and about 180 mmwide. The material of the wipe may generally be soft and flexible,potentially having a structured surface to enhance its cleaningperformance.

The wet wipes may also be treated to improve the softness and texturethereof by processes such as hydroentanglement or spunlacing. The wetwipes may be subjected to various treatments, such as, but not limitedto, physical treatment, such as ring rolling, as described in U.S. Pat.No. 5,143,679; structural elongation, as described in U.S. Pat. No.5,518,801; consolidation, as described in U.S. Pat. Nos. 5,914,084,6,114,263, 6,129,801 and 6,383,431; stretch aperturing, as described inU.S. Pat. Nos. 5,628,097, 5,658,639 and 5,916,661; differentialelongation, as described in WO Publication No. 2003/0028165A1; and othersolid state formation technologies as described in U.S. Publication No.2004/0131820A1 and U.S. Publication No. 2004/0265534A1 and zoneactivation and the like; chemical treatment, such as, but not limitedto, rendering part or all of the substrate hydrophobic, and/orhydrophilic, and the like; thermal treatment, such as, but not limitedto, softening of fibers by heating, thermal bonding and the like; andcombinations thereof.

The wet wipe may have a basis weight of at least about 40 grams/m². Inone example, the wipe may have a basis weight of at least about 45grams/m². In another example, the wet wipe basis weight may be less than120 grams/m². In another example, wet wipe may have a basis weight offrom about 45 grams/m² to about 90 grams/m² and/or from about 50 g/m² toabout 80 g/m².

In one example of the present invention the surface of wet wipe may beessentially flat. In another example of the present invention thesurface of the wet wipe may optionally contain raised and/or loweredportions. These can be in the form of logos, indicia, trademarks,geometric patterns, images of the surfaces that the substrate isintended to clean (i.e., infant's body, face, etc.). They may berandomly arranged on the surface of the wipe or be in a repetitivepattern of some form.

In another example of the present invention the wet wipe may bebiodegradable. For example the wet wipe could be made from abiodegradable material such as a polyesteramide, or high wet strengthcellulose.

“Liquid composition” as used herein means any liquid including, but notlimited to a pure liquid such as water, an aqueous composition, acolloid, an emulsion, a suspension, a solution and mixtures thereof. Theterm “aqueous composition” as used herein refers to a composition thatcomprises at least 20% and/or at least 40% and/or at least 50% and/or toabout 98% and/or to about 95% and/or to about 93% and/or to about 90% byweight water.

In one example, the liquid composition comprises water or another liquidsolvent. Generally the liquid composition is of sufficiently lowviscosity to impregnate the entire structure of the fibrous structure.In another example, the liquid composition may be primarily present on asurface of the fibrous structure surface and to a lesser extent in theinner structure of the fibrous structure. In a further example, theliquid composition is releasably carried by the fibrous structure, thatis the liquid composition is carried on or in the fibrous structure andis readily releasable from the fibrous structure by applying some forceto the fibrous structure, for example by wiping a surface, such as ahuman skin, with the fibrous structure.

The liquid composition of the present invention may comprise anoil-in-water emulsion. In one example, the liquid composition of thepresent invention comprises at least 80% and/or at least 85% and/or atleast 90% and/or at least 95% by weight water.

When present on and/or in the fibrous structure of the presentinvention, the liquid composition may be present at a level of fromabout 10% to about 1000% of the basis weight of the fibrous structureand/or from about 100% to about 700% of the basis weight of the fibrousstructure and/or from about 200% to about 400% of the basis weight ofthe fibrous structure.

The liquid composition may comprise an acid. Non-limiting examples ofacids that can be used in the liquid composition of the presentinvention are adipic acid, tartaric acid, citric acid, maleic acid,malic acid, succinic acid, glycolic acid, glutaric acid, malonic acid,salicylic acid, gluconic acid, polymeric acids, phosphoric acid,carbonic acid, fumaric acid and phthalic acid and mixtures thereof.Suitable polymeric acids can include homopolymers, copolymers andterpolymers, and may contain at least 30 mole % carboxylic acid groups.Specific examples of suitable polymeric acids useful herein includestraight-chain poly(acrylic) acid and its copolymers, both ionic andnonionic, (e.g., maleic-acrylic, sulfonic-acrylic, and styrene-acryliccopolymers), those cross-linked polyacrylic acids having a molecularweight of less than about 250,000, preferably less than about 100,000poly(α-hydroxy) acids, poly(methacrylic) acid, and naturally occurringpolymeric acids such as carageenic acid, carboxy methyl cellulose, andalginic acid. In one example, the liquid composition comprises citricacid and/or citric acid derivatives.

The liquid composition may also contain salts of the acid or acids,which may help to lower the pH of the liquid composition, or anotherweak base to impart buffering properties to the fibrous structure. Thebuffering response is due to the equilibrium which is set up between thefree acid and its salt. This allows the fibrous structure to maintainits overall pH despite encountering a relatively high amount of bodilywaste as would be found post urination and/or defecation in a baby oradult. In one embodiment the acid salt comprises sodium citrate. Theamount of sodium citrate present in the liquid composition in oneexample may be between 0.01 and 2.0%, alternatively 0.1 and 1.25%, oralternatively 0.2 and 0.7% by weight of the liquid composition.

In addition to the above ingredients, the liquid composition maycomprise additional ingredients. Non-limiting examples of additionalingredients that may be present in the liquid composition of the presentinvention include: skin conditioning agents (emollients, humectants)including, waxes such as petrolatum, cholesterol and cholesterolderivatives, di and tri-glycerides including sunflower oil and sesameoil, silicone oils such as dimethicone copolyol, caprylyl glycol andacetoglycerides such as lanolin and its derivatives, emulsifiers;alcohols; preservatives; stabilizers; surfactants including anionic,amphoteric, cationic and non ionic surfactants, colorants, chelatingagents including EDTA, sun screen agents, solubilizing agents, perfumes,opacifying agents, vitamins, viscosity modifiers; such as xanthan gum,astringents and external analgesics.

In one example, the liquid composition comprises an alcohol, such asbenzylalcohol.

In one example, the liquid composition comprises a perfume.

In one example, the liquid composition comprises a preservative. Inanother example, the liquid composition is void of a preservative.

The liquid composition prior to contacting the fibrous structure of thepresent invention may exhibit a pH of greater than 5 and/or greater than5.2 and/or greater than 5.5 and/or greater than 6 and/or less than 10and/or less than 9 and/or less than 8 and/or less than 7 as measuredaccording to the pH Test Method described herein prior to contacting thefibrous structure.

The pH of the liquid composition may be impacted by the fibrousstructure, for example the fiber composition of the fibrous structure.The liquid composition may exhibit a pH of less than 4.55 and/or lessthan 4.3 and/or less than 4.1 and/or less than 4 and/or less than 3.8and/or greater than 2 and/or greater than 2.5 and/or greater than 3and/or greater than 3.5 as measured according to the pH Test Methoddescribed herein after being extracted from the fibrous structure.

Table 1 below shows the pH of the liquid composition after beingextracted from the fibrous structure of the present invention and knownwet wipes.

TABLE 1 pH of Liquid Composition Wet Wipe Extracted from Wet WipeInvention Example1 4.3 Invention Example 2 4.3 Invention Example 3 4.3Invention Example 4 4.3 Invention Example 5 4.3 Invention Example 6 4.3Charmin Freshmates (currently marketed) 4.62 Kleenex Cottonelle Fresh5.03 Walgreens Flushable Moist Wipes 5.09 Walmart Natural ChoiceFlushable Moist 5.19 Wipes Kroger Nice n Soft Flushable Moist Wipes 5.05Meijer Flushable Moist Wipes 5.23 Target Up&Up Flushable Moist Wipes5.04 Scott Wipes 5.08

In one example, the liquid composition comprises an alcohol. In anotherexample, the liquid composition comprises a perfume. In still anotherexample, the liquid composition comprises a preservative.

“% Saturation” also equivalently referred to as “saturation loading” asused herein means the amount of a liquid composition applied to afibrous structure to form a wet wipe. In general, the amount of theliquid composition applied to a fibrous structure according to thepresent invention may be chosen in order to provide maximum benefits tothe wet wipe. Saturation loading, often expressed as percent saturation,is defined as the percentage of the dry fibrous structure's mass thatthe liquid composition mass represents. For example, a saturation loadof 1.0 (equivalently 100% saturation) indicates that the mass of theliquid composition contained in/on the fibrous structure is equal to thefibrous structure mass whereas a saturation load of 1.5 (equivalently150% saturation) indicates that the mass of the liquid compositioncontained in/on the fibrous structure is 1.5 times the fibrous structuremass.

The wet wipes and/or fibrous structures of the present invention mayexhibit a basis weight of greater than 15 g/m² (9.2 lbs/3000 ft²) toabout 120 g/m² (73.8 lbs/3000 ft²) and/or from about 15 g/m² (9.2lbs/3000 ft²) to about 110 g/m² (67.7 lbs/3000 ft²) and/or from about 20g/m² (12.3 lbs/3000 ft²) to about 100 g/m² (61.5 lbs/3000 ft²) and/orfrom about 30 (18.5 lbs/3000 ft²) to 90 g/m² (55.4 lbs/3000 ft²). Inaddition, the wet wipes and/or fibrous structures of the presentinvention may exhibit a basis weight between about 40 g/m² (24.6lbs/3000 ft²) to about 120 g/m² (73.8 lbs/3000 ft²) and/or from about 50g/m² (30.8 lbs/3000 ft²) to about 110 g/m² (67.7 lbs/3000 ft²) and/orfrom about 55 g/m² (33.8 lbs/3000 ft²) to about 105 g/m² (64.6 lbs/3000ft²) and/or from about 60 (36.9 lbs/3000 ft²) to 100 g/m² (61.5 lbs/3000ft²).

The wet wipes of the present invention may exhibit an initial total wettensile strength of less than 3000 g/in and/or less than 2500 g/inand/or less than 2000 g/in and/or less than 1800 g/in and/or less than1500 g/in and/or less than 1250 g/in and/or greater than 300 g/in and/orgreater than 400 g/in and/or greater than 500 g/in and/or greater than600 g/in as measured according to the Wet Tensile Strength Test Methoddescribed herein. In one example, the wet wipes of the present inventionmay exhibit a total wet tensile strength after 28 days of less than 2000g/in and/or less than 1800 g/in and/or less than 1500 g/in and/or lessthan 1250 g/in and/or less than 1000 g/in and/or greater than 100 g/inand/or greater than 200 g/in and/or greater than 300 g/in and/or greaterthan 400 g/in as measured according to the Wet Tensile Strength TestMethod described herein.

The wet wipes of the present invention may exhibit a density (measuredat 95 g/in²) of less than about 0.60 g/cm³ and/or less than about 0.30g/cm³ and/or less than about 0.20 g/cm³ and/or less than about 0.10g/cm³ and/or less than about 0.07 g/cm³ and/or less than about 0.05g/cm³ and/or from about 0.01 g/cm³ to about 0.20 g/cm³ and/or from about0.02 g/cm³ to about 0.10 g/cm³.

The wet wipes of the present invention may be in the form of wet wiperolls. Such wet wipe rolls may comprise a plurality of connected, butperforated sheets of fibrous structure, that are separably dispensablefrom adjacent sheets.

The wet wipes of the present invention may comprises additives such assoftening agents such as silicones and/or quaternary ammonium compounds,temporary wet strength agents, permanent wet strength agents, bulksoftening agents, lotions, silicones, wetting agents, latexes,especially surface-pattern-applied latexes, dry strength agents such ascarboxymethylcellulose and starch, and other types of additives suitablefor inclusion in and/or on wet wipes.

In one example, the wet wipe is void (less than 5% and/or less than 3%and/or less than 1% and/or less than 0.5% and/or less than 0.1% byweight of the wet wipe) of any post fibrous structure making appliedpolymeric binder.

“Weight average molecular weight” as used herein means the weightaverage molecular weight as determined using gel permeationchromatography according to the protocol found in Colloids and SurfacesA. Physico Chemical & Engineering Aspects, Vol. 162, 2000, pg. 107-121.

“Basis Weight” as used herein is the weight per unit area of a samplereported in lbs/3000 ft² or g/m² and is measured according to the BasisWeight Test Method described herein.

“Caliper” as used herein means the macroscopic thickness of a fibrousstructure. Caliper is measured according to the Caliper Test Methoddescribed herein.

“Bulk” as used herein is calculated as the quotient of the Caliper,expressed in microns, divided by the Basis Weight, expressed in gramsper square meter. The resulting Bulk is expressed as cubic centimetersper gram. For the products of this invention, Bulks can be greater thanabout 3 cm³/g and/or greater than about 6 cm³/g and/or greater thanabout 9 cm³/g and/or greater than about 10.5 cm³/g up to about 30 cm³/gand/or up to about 20 cm³/g. The products of this invention derive theBulks referred to above from the basesheet, which is the sheet producedby the tissue machine without post treatments such as embossing.Nevertheless, the basesheets of this invention can be embossed toproduce even greater bulk or aesthetics, if desired, or they can remainunembossed. In addition, the basesheets of this invention can becalendered to improve smoothness or decrease the Bulk if desired ornecessary to meet existing product specifications.

“Density” as used herein is calculated as the quotient of the BasisWeight expressed in grams per square meter divided by the Caliperexpressed in microns. The resulting Density is expressed as grams percubic centimeters (g/cm³ or g/cc). In one example, the Densities can begreater than 0.05 g/cm³ and/or greater than 0.06 g/cm³ and/or greaterthan 0.07 g/cm³ and/or less than 0.10 g/cm³ and/or less than 0.09 g/cm³and/or less than 0.08 g/cm³. In one example, a fibrous structure of thepresent invention exhibits a density of from about 0.055 g/cm³ to about0.095 g/cm³.

“Machine Direction” or “MD” as used herein means the direction parallelto the flow of the fibrous structure through the fibrous structuremaking machine and/or wet wipe manufacturing equipment.

“Cross Machine Direction” or “CD” as used herein means the directionparallel to the width of the fibrous structure making machine and/or wetwipe manufacturing equipment and perpendicular to the machine direction.

“Ply” as used herein means an individual, integral fibrous structure.

“Plies” as used herein means two or more individual, integral fibrousstructures disposed in a substantially contiguous, face-to-facerelationship with one another, forming a multi-ply fibrous structureand/or multi-ply wet wipe. It is also contemplated that an individual,integral fibrous structure can effectively form a multi-ply fibrousstructure, for example, by being folded on itself.

“Embossed” as used herein with respect to a fibrous structure means afibrous structure that has been subjected to a process which converts asmooth surfaced fibrous structure to a decorative surface by replicatinga design on one or more emboss rolls, which form a nip through which thefibrous structure passes. Embossed does not include creping,microcreping, printing or other processes that may impart a textureand/or decorative pattern to a fibrous structure.

Fibrous Structure

In one example of the present invention, the fibrous structure of thewet wipe comprises greater than 20% and/or greater than 40% and/orgreater than 50% and/or greater than 75% and/or greater than 90% and/orto about 100% by weight on a total dry fiber basis of pulp fibers, suchas hardwood and/or softwood pulp fibers.

The fibrous structure may comprise a surface comprising a surfacepattern. The surface pattern may comprise a non-random, repeatingpattern. The surface pattern may comprise a formed surface pattern suchas resulting from a patterned belt and/or belt/fabric combination. Inanother example, the fibrous structure may be an embossed fibrousstructure that comprises one or more embossments, such as imparted bypassing the fibrous structure (prior to and/or after application of aliquid composition) through an embossing nip. The one or moreembossments may comprise line art embossments and/or dot embossmentsand/or other non-line art embossments.

In one example, the fibrous structure of the present invention maycomprise two or more regions that are different from one another withrespect to their specific level of wet tensile strength and/orresistance to disperse.

As shown in FIGS. 1 and 2, a fibrous structure 10 according to thepresent invention may comprise a surface 12 comprising a surface pattern14. The surface pattern 14 may include two or more different regions. Inone example, the surface pattern 14 includes discrete, higher densityregions 16 and a lower density region 18 compared to the discrete,higher density regions 16. The lower density region 18 may be in theform of a continuous or substantially continuous network surrounding thediscrete, higher density regions 16. In one example, the discrete,higher density regions 16 comprise greater than 6% to about 65% of thesurface pattern. In another example, the surface pattern 14 comprisesfrom about 8 to about 400 discrete, higher density regions 16. Thediscrete, higher density regions 16 may comprise any shape orcombination of shapes, for example, circles, triangles, diamonds,trapezoids, squares, rectangles, parallelograms, rhombuses, stars,pentagons, hexagons, and octagons. Without wishing to be bound bytheory, it is believed that the lower density region 18 disperses morereadily than the higher density regions 16. However, as shown in FIGS. 3and 4, the fibrous structure 10 of the present invention may comprise asurface 12 having a surface pattern 14 that includes discrete, lowerdensity regions 20, sometimes referred to as “pillows” and a higherdensity region 22, sometimes referred to as a “knuckle.” The higherdensity region 22 may be in the form of a continuous or substantiallycontinuous network surrounding the discrete, lower density regions 20.

In another example of the present invention as shown in FIGS. 5 and 6, afibrous structure 10 may comprise a surface 12 having a surface pattern14. The surface pattern 14 may comprise discrete, higher density regions24 and discrete, lower density regions 26.

In another example of the present invention, the fibrous structurecomprises two or more regions that exhibit different values of a commonintensive property, for example different densities (a region of higherdensity relative to a region of lower density) and/or different basisweights.

The fibrous structure may be a creped fibrous structure or an uncrepedfibrous structure. The fibrous structure may be a fabric and/or beltcreped fibrous structure. In addition, the fibrous structure may be awet molded and/or a wet microcontracted fibrous structure. Further, thefibrous structure may be a through-air-dried fibrous structure or acompressively dewatered fibrous structure, such as a conventionalpapermaking processed fibrous structure. In one example, the fibrousstructure is a non-hydroentangled (non-spunlaced) fibrous structure.

The fibrous structure may comprise a temporary wet strength agent.Suitable temporary wet strength agents include materials that can reactwith hydroxyl groups, such as on cellulosic pulp fibers, to formhemiacetal bonds that are reversible in the presence of excess water.Suitable temporary wet strength agents are known to those of ordinaryskill in the art. Non-limiting examples of temporary wet strength agentssuitable for the fibrous structures of the present invention includeglyoxylated polyacrylamide polymers, for example cationic glyoxylatedpolyacrylamide polymers. In one example, the temporary wet strengthagent comprises Hercobond® commercially available from Ashland Inc. Inanother example, the temporary wet strength agent comprises Parez® 750and/or 745 commercially available from Kemira Chemicals, Inc.

In one example, the temporary wet strength agent exhibits a pH of lessthe 7 and/or less than 6.5 and/or less than 6 and/or less than 5.5and/or less than 5 and/or less than 4.5 and/or to about 2.5 and/or toabout 3 and/or to about 3.5. In one example, the pH of the temporary wetstrength agent is about 4.

Non-limiting examples of temporary wet strength agents made by themethods of the present invention generally have weight average molecularweights of from about 20,000 to about 400,000 and/or from about 50,000to about 400,000 and/or from about 70,000 to about 400,000 and/or fromabout 70,000 to about 300,000 and/or from about 100,000 to about200,000.

The temporary wet strength agents of the present invention impart wettensile strength properties and wet tensile decay properties to thefibrous structures and/or wet wipes of the present invention.

It has been found that temporary wet strength agents with high weightaverage molecular weights (i.e. those in excess of 300,000) may decayunacceptably slow for consumer purposes. Further, it has been found thattemporary wet strength agents with extremely low weight averagemolecular weights (i.e. those less than 70,000) may have very low wetstrength and may not be optimal as temporary wet strength agents forfibrous structures and/or wet wipes.

Non-limiting examples of temporary wet strength agents in accordancewith the present invention include temporary wet strength agents havingthe formula:

wherein: A (the moiety present on the co-crosslinking monomeric unit) isindependently an electrophilic moiety, non-limiting examples of whichinclude the following:

Z (the moiety present on the reversible, homo-crosslinking monomericunit) is independently a nucleophilic moiety capable of forming anunstable covalent bond with the electrophilic moiety, non-limitingexamples of which include the following:

and X is independently —O—, —NH—, or —NCH₃—; and R₁ is a substituted orunsubstituted aliphatic group; Y₁, Y₂, and Y₃ are independently —H,—CH₃, or a halogen; Q is a cationic moiety; and W is a non-nucleophilicmoiety or a nucleophilic moiety that does not form a stable covalentbond with the electrophilic moiety. Non-limiting examples of moietiesfor W include water-soluble N,N-dialkyl acrylamide moieties and/orwater-soluble carboxylic acid moieties.

The mole percent of a ranges from about 1% to about 20%, preferably fromabout 2% to about 15%, the mole percent of b ranges from about 0% toabout 60%, preferably from about 0% to about 45%, the mole percent of cranges from about 10% to about 90%, preferably from about 30% to about80%, and d ranges from about 1% to about 40%, preferably from about 2%to about 20%, more preferably from about 5% to about 12%.

Unless otherwise expressly specified, values for a, b, c, and d shall bemole percentage values based upon the average number of monomeric unitsin the polymer backbone of the temporary wet strength agent of thepresent invention.

The monomeric units of the polymer backbone of the temporary wetstrength agent of the present invention may be randomly distributedthroughout the polymer in ratios corresponding to the mole percentageranges described herein.

Each class of monomeric units may include a single monomer or mayinclude combinations of two or more different monomers within thatclass. The mole percent of each monomeric unit within a class ofmonomeric units may be independently selected.

In one example, the fibrous structure comprises greater than 5% and/orgreater than 10% and/or greater than 25% and/or greater than 40% and/orgreater than 50% and/or to about 90% and/or to about 80% and/or to about70% by weight of the liquid composition.

Wet Wipe

The fibrous structures of the present invention may be saturation loadedwith a liquid composition to form a wet wipe. The loading may occurindividually, or after the fibrous structures are placed in a stack,such as within a liquid impervious container or packet. In one example,the fibrous structures may be saturation loaded with from about 1.5 g toabout 6.0 g and/or from about 2.5 g to about 4.0 g of liquid compositionper g of fibrous structure.

The wet wipes of the present invention may be placed in the interior ofa container, which may be liquid impervious, such as a plastic tub or asealable packet, for storage and eventual sale to the consumer. The wetwipes may be folded and stacked. The wet wipes of the present inventionmay be folded in any of various known folding patterns, such asC-folding, Z-folding and quarter-folding. Use of a Z-fold pattern mayenable a folded stack of wet wipes to be interleaved with overlappingportions. Alternatively, the wet wipes may include a continuous strip offibrous structure which has perforations between each wet wipe and whichmay be arranged in a stack or wound into a roll for dispensing, oneafter the other, from a container, which may be liquid impervious.

The wet wipes of the present invention may further comprise prints,which may provide aesthetic appeal. Non-limiting examples of printsinclude figures, patterns, letters, pictures and combinations thereof.

In one example, the wet wipe of the present invention exhibits an in-usetotal wet tensile strength of greater than 300 g/in and/or greater than400 g/in and/or greater than 500 g/in and/or greater than 600 g/inand/or less than 2500 g/in and/or less than 2000 g/in and/or less than1500 g/in and/or less than 1000 g/in as measured by the Wet TensileStrength Test Method described herein.

In another example, the wet wipe of the present invention exhibits a12.5 mm Screen Retention Value at 3 hours of less than 50% and/or lessthan 40% and/or less than 30% and/or 20% and/or less than 15% and/orless than 10% and/or less than 5% as measured according to the ShakeFlask Test Method described herein.

In another example, the wet wipe of the present invention exhibits a 3mm Screen Retention Value at 3 hours of less than 50% and/or less than40% and/or less than 30% and/or less than 25% and/or less than 20%and/or less than 15% and/or less than 10% and/or less than 5% asmeasured according to the Shake Flask Test Method described herein.

Table 2 below shows the Screen Retention Values for several inventionexample wet wipes that comprised 7 pounds/ton of temporary wet strengthagent (Hercobond® 1194), a first prototype (Prototype 1) that wassimilar to the invention example wet wipes except it contained 12pounds/ton temporary wet strength agent (Hercobond® 1194), twoprototypes (Prototypes 2 and 3) that were similar to the inventionexample wet wipes except they contained a permanent wet strength agent(Kymene®) rather than a temporary wet strength agent, and known wetwipes.

TABLE 2 12.5 mm Screen 3 mm Screen Retention Retention Value (%) Value(%) Wet Wipe After 3 hours After 3 hours Invention Example 1 0 19Invention Example 2 0 0 Invention Example 3 0 0 Invention Example 4 05.5 Invention Example 5 0 0 Invention Example 6 2.4 20.1 CharminFreshmates 83.2 70 (currently marketed) Prototype 1 — 70 Prototype 2 9292 (permanent wet strength agent) Prototype 3 95 95 (permanent wetstrength agent) Kleenex Cottonelle 0 28 Fresh Walgreens Flushable 90.6 0Moist Wipes Walmart Natural — — Choice Flushable Moist Wipes* KrogerNice n Soft 90.8 0 Flushable Moist Wipes Meijer Flushable — — MoistWipes* Target Up&Up — — Flushable Moist Wipes* Scott Natural Wipes 23.05.1 Unicharm Wipes — 12 *Expect the values for these products to beconsistent with the values of the Walgreens and the Kroger productssince their fibrous structures are apparently supplied by the samesupplier; namely Rockline Industries.Method for making Fibrous structure

Any suitable process known in the art may be used to make the fibrousstructure of the present invention. In one example, the fibrousstructure of the present invention is made using a wet-laid fibrousstructure making process.

The fibrous structure of the present invention may be made by anysuitable process known in the art so long as the fibrous structure meetsthe wet tensile strength and/or dispersibility requirements describedherein. In one example, the fibrous structure of the present inventionis made using a wet-laid fibrous structure making process.

In one example, a method for making a wet wipe comprising the steps of:

-   -   a. providing a fibrous structure, for example a fibrous        structure according to the present invention; and    -   b. contacting the fibrous structure with a liquid composition,        for example a fibrous structure according to the present        invention such that a wet wipe, for example a wet wipe according        to the present invention is produced.

In still another example, a method for making a wet wipe comprising thesteps of:

-   -   a. providing a fibrous structure, for example a fibrous        structure according to the present invention; and    -   b. contacting the fibrous structure with a liquid composition,        for example a liquid composition according to the present        invention such that the pH of the liquid composition after being        extracted from the fibrous structure is less than 4.55 as        measured according to the pH Test Method to produce a wet wipe,        for example a wet wipe according to the present invention.

In yet another example, a method for making a wet wipe comprising thesteps of:

-   -   a. providing a fibrous slurry comprising a plurality of fibers        and a temporary wet strength agent; and optionally, a dry        strength agent;    -   b. depositing the fibrous slurry onto a forming wire to form an        embryonic web;    -   c. transferring the embryonic web to a patterned belt to impart        a surface pattern to the embryonic web;    -   d. drying the embryonic web to form a fibrous structure, for        example a fibrous structure according to the present invention;        and    -   e. contacting the fibrous structure with a liquid composition,        for example a liquid composition according to the present        invention to form a wet wipe, for example a wet wipe according        to the present invention.

In yet another example, a method for making a wet wipe comprising thesteps of:

-   -   a. providing a fibrous slurry comprising a plurality of fibers        and a temporary wet strength agent; and optionally, a dry        strength agent;    -   b. depositing the fibrous slurry onto a forming wire to form an        embryonic web;    -   c. transferring the embryonic web to a patterned belt to impart        a surface pattern to the embryonic web;    -   d. drying the embryonic web to form a fibrous structure, for        example a fibrous structure according to the present invention;        and    -   e. contacting the fibrous structure with a liquid composition,        for example a liquid composition according to the present        invention to form a wet wipe, for example a wet wipe according        to the present invention wherein the pH of the liquid        composition after being extracted from the fibrous structure is        less than 4.55 as measured according to the pH Test Method, is        provided.

The fibrous structure may be any suitable fibrous structure. In oneexample, the fibrous structure comprises a wet-laid fibrous structure.

In another example, the fibrous structure comprises greater than 75%and/or greater than 80% and/or greater than 90% and/or greater than 95%and/or to about 100% by weight of pulp fibers.

The patterned belt of the present invention may be a molding member. A“molding member” is a structural element that can be used as a supportfor an embryonic web comprising a plurality of cellulosic fibers and aplurality of synthetic fibers, as well as a forming unit to form, or“mold,” a desired microscopical geometry of the wet wipe of the presentinvention. The molding member may comprise any element that hasfluid-permeable areas and the ability to impart a microscopicalthree-dimensional pattern to the structure being produced thereon, andincludes, without limitation, single-layer and multi-layer structurescomprising a stationary plate, a belt, a woven fabric (includingJacquard-type and the like woven patterns), a band, and a roll. In oneexample, the molding member is a deflection member. The molding membermay comprise a surface pattern according to the present invention thatis imparted to the wet wipe during the wet wipe making process.

A “reinforcing element” is a desirable (but not necessary) element insome embodiments of the molding member, serving primarily to provide orfacilitate integrity, stability, and durability of the molding membercomprising, for example, a resinous material. The reinforcing elementcan be fluid-permeable or partially fluid-permeable, may have a varietyof embodiments and weave patterns, and may comprise a variety ofmaterials, such as, for example, a plurality of interwoven yarns(including Jacquard-type and the like woven patterns), a felt, aplastic, other suitable synthetic material, or any combination thereof.

In one example of a method for making a wet wipe of the presentinvention, the method comprises the step of contacting an embryonicfibrous web with a deflection member (molding member) such that at leastone portion of the embryonic fibrous web is deflected out-of-plane ofanother portion of the embryonic fibrous web. The phrase “out-of-plane”as used herein means that the wet wipe comprises a protuberance, such asa dome, or a cavity that extends away from the plane of the wet wipe.The molding member may comprise a through-air-drying fabric having itsfilaments arranged to produce linear elements within the wet wipes ofthe present invention and/or the through-air-drying fabric or equivalentmay comprise a resinous framework that defines deflection conduits thatallow portions of the wet wipe to deflect into the conduits thus forminglinear elements within the wet wipes of the present invention. Inaddition, a forming wire, such as a foraminous member may be arrangedsuch that linear elements within the wet wipes of the present inventionare formed and/or like the through-air-drying fabric, the foraminousmember may comprise a resinous framework that defines deflectionconduits that allow portions of the wet wipe to deflect into theconduits thus forming linear elements within the wet wipes of thepresent invention.

The step of contacting the fibrous structure with a liquid compositionmay comprise spraying, dipping, extruding, and/or printing the liquidcomposition onto the fibrous structure.

In one example, the liquid composition exhibits a pH of greater than 5and/or greater than 5.2 and/or greater than 5.5 and/or greater than 6and/or less than 10 and/or less than 9 and/or less than 8 and/or lessthan 7 as measured according to the pH Test Method described hereinprior to contacting the fibrous structure.

The liquid composition may exhibit a pH of less than 4.55 and/or lessthan 4.3 and/or less than 4.1 and/or less than 4 and/or less than 3.8and/or greater than 2 and/or greater than 2.5 and/or greater than 3and/or greater than 3.5 as measured according to the pH Test Methoddescribed herein after being extracted from the fibrous structure.

In one example, the liquid composition comprises an alcohol. In anotherexample, the liquid composition comprises a perfume. In still anotherexample, the liquid composition comprises a preservative.

Any suitable level of the liquid composition may be delivered to thefibrous structure. In one example, the fibrous structure comprisesgreater than 5% and/or greater than 10% and/or greater than 25% and/orgreater than 40% and/or greater than 50% and/or to about 90% and/or toabout 80% and/or to about 70% by weight of the liquid composition.

Any suitable level of the temporary wet strength agent may be added tothe fibrous slurry. In one example, the temporary wet strength agent isadded to the fibrous slurry at a level of greater than 0.1 and/orgreater than 0.5 and/or greater than 1 and/or greater than 3 and/orgreater than 5 and/or greater than 6 and/or to less than 12 and/or lessthan 10 and/or less than 8 pounds/ton of fiber.

Before or after the contacting step, the fibrous structure may convertedinto a wet wipe.

The fibrous structure may be in a roll form, such as a parent roll fromthe fibrous structure making process. A roll of fibrous structure may beconverted into rolls of wet wipes and/or individual sheets of wet wipes.

In one example a roll of fibrous structure may be unwound and slit intosmaller widths of fibrous structures that may then be wound into smallerwidth rolls, for example 188 mm width rolls.

The rolls of fibrous structure may be loaded into a converting line'sunwind stand. The unwind stand may be a center driven unwind standcapable of controlling the tension via speed control through a series ofdancers. In one example, the line speed at this stage in the convertingline is about 34 m/min. The fibrous structure then may pass over thedancers and a tensiometer device that monitors tension of the fibrousstructure inline while being converted with real time feedback to thecenter drive unwind stand to control in process tension monitoring andcontrol. In one example, the inline converting tension of the fibrousstructure may be about 1 N.

The fibrous structure may then pass over a liquid composition bar (alsoreferred to as a lotion bar) with minimal contact such that the lotionbar delivers the liquid composition through openings in the lotion barto a surface of the fibrous structure.

The fibrous structure may then be folded into any suitable foldconfiguration, such as a Z-fold. This folding step may occur prior tothe fibrous structure passing over the liquid composition bar.

In one example, the folded fibrous structure may be cut to desireddimensions to form individual wet wipes. A plurality of the individualwet wipes may be stacked together and then packaged in a containerand/or wrapper.

In another example, the folded fibrous structure may be perforated andthen wound into a roll of perforated wet wipes, which may be dispensedfrom the roll as individual wet wipes upon tearing along a perforation.

A container and/or wrapper containing a stack of wet wipes or a roll ofwet wipes forms an article of manufacture that may be sold to consumers.

In one example, the fibrous structure making process may be directlycoupled or close coupled to the converting line.

In another example, the fibrous structure making process may compriseslitting the fibrous structure prior to moving to the converting line.

Non-Limiting Example

One example of a process for making a wet wipe is as follows. A wet wipein accordance with the present invention is prepared using a fibrousstructure made by a fibrous structure making machine having anon-layered headbox.

A conventional pulper is used to prepare the hardwood stock chest witheucalyptus fiber having a consistency of about 3.0% by weight to form athick stock. Separately, a conventional pulper is used to prepare thesoftwood stock chest with northern softwood kraft (NSK) fiber having aconsistency of about 3.0% by weight to form a thick stock. The NSK fiberis passed through a refiner and is refined to a Canadian StandardFreeness (CSF) of about 650. After refining, a temporary wet strengthagent, Hercules Hercobond® 1194 at 1% solids, is added to the NSK thickstock at a rate of about 6.1 pounds per ton of fiber. The refined NSKthick stock and the Eucalyptus thick stock are then combined into acommon stock line at an in-line mixer to form a homogeneous thick stockat a proportion of 70% NSK and 30% Eucalyptus.

The homogeneous thick stock is pumped to the fan pump where it isdiluted from about 3% consistency to about 0.1% to about 0.2%consistency with process water having a pH of about 5.2 to about 5.5.Once diluted, the homogeneous slurry is pumped to the headbox where thefiber slurry is evenly distributed onto a forming wire (84×78, AlbanyInternational) traveling at a velocity of 220 feet per minute to form anembryonic web. The vacuum slots located on the wire table vacuum areused to dewater the embryonic web to a consistency of about 20% to about25% before entering the wire-to-press transfer zone.

A pickup shoe is used to transfer the embryonic web from the formingwire to a patterned drying belt. The speed of the patterned drying beltis about 200 feet per minute. The drying belt is designed to mold apattern of substantially discrete high density regions surrounded by acontinuous network of low density regions into the embryonic web. Thedrying belt is formed by casting an impervious resin surface onto afiber mesh supporting fabric. The supporting fabric is a 98×62 filament,dual layer mesh. The thickness of the resin cast is about 22 mils abovethe supporting fabric.

While remaining in contact with the patterned drying belt, the web ispre-dried by air blow-through pre-dryers to a fiber consistency of about60% by weight.

After the pre-dryers, the semi-dry web is transferred to the Yankeedryer via pressure roll nip and adhered to the surface of the Yankeedryer with a sprayed a creping adhesive coating. The creping adhesive isan aqueous dispersion with the actives consisting of Georgia Pacific'sUnicrepe 457T20 and Vinylon Works' Vinylon 8844 at a blend of about25%/75%, respectively. The fiber consistency is increased to about 97%before the web is dry-creped from the Yankee with a doctor blade.

The doctor blade has a bevel angle of about 45 degrees and is positionedwith respect to the Yankee dryer to provide an impact angle of about 101degrees. The Yankee dryer is operated at a temperature of about 350° F.(177° C.) and a speed of about 200 feet per minute. The fibrousstructure is wound into a parent roll using a surface driven reel drumhaving a surface speed of about 191 feet per minute.

The parent roll width is slit to a width of 188 millimeters as itrewound into a “chip” roll. The “chip” is placed onto the unwind standand the fibrous web is threaded through a wet wipe converting line. Thespeed of the fibrous web through the process is 34 meters per minutewhile the fibrous web tension is controlled to about 1 Newton. Thefibrous web then passes over a lotion bar (liquid composition bar) wherethe fibrous web absorbs the lotion (liquid composition) at a saturationlevel of about 150% to about 200%.

The lotion-saturated fibrous web is then folded in a Z-foldconfiguration (ribbon), cut to length, stacked, and optionallyinterleaved to form a stack of wet wipes, which then are placed into awrapper or container, such as a tub.

Test Methods

Unless otherwise indicated, all tests described herein including thosedescribed under the Definitions section and the following test methodsare conducted on samples that have been conditioned in a conditionedroom at a temperature of 23° C.±2.2° C. and a relative humidity of50%±10% for 2 hours prior to the test. All tests are conducted in suchconditioned room.

pH Test Method

In order to measure the pH of a liquid composition present on a wetwipe, the following procedure is used. First, secure a C-clamp's framein the jaws of a 6 inch table vise. Tighten the table vise so that theC-clamp does not move. The C-clamp should not shift within the tablevise as compression is formed between the stationary foot and theadjustable foot of the C-clamp. The feet of the C-clamp have a 1 inchdiameter.

Calibrate a digital pH meter (Oakton pH 5, Acorn Series, WD-35613-00 orequivalent) according to the manufacturer's instruction manual.Measurements are made according to the manufacturer's instructionmanual.

Wearing latex or rubber gloves, dispense a single sheet of wet wipe froma package or tub of wet wipes being sure that the wet wipe has not driedout too much. Fold the single wet wipe sheet five times (resulting in a32-ply implement).

Place the folded wet wipe sheet onto the stationary foot of the C-clamp.Turn the adjustment screw for the adjustable foot of the C-clamp untilthe stationary and adjustable foot of the C-clamp contact the folded wetwipe sheet.

Position a 50 ml beaker under the folded wet wipe sheet and then turnthe adjustment screw of the C-clamp to begin compressing the folded wetwipe sheet to cause the liquid composition to flow from the folded wetwipe sheet and collect the liquid composition into the 50 ml beaker.

Repeat the steps of this procedure with additional wet wipes from thepackage or tub until the level of extricated liquid composition in the50 ml beaker is sufficient for measuring pH per the pH metermanufacturer's instruction manual.

Measure and record the resulting pH for the wet wipe.

One of ordinary skill in the art will understand how to measure the pHof a liquid composition prior to contacting a fibrous structure and/or atemporary wet strength agent.

Shake Flask Test Method

To determine the dispersibility of a wet wipe, the following Shake FlaskTest is performed. The results of this test show the Screen RetentionValue of a wet wipe at various size screens.

Sample Preparation: Weigh a wet wipe to be tested. Incubate a wet wipesample in a 2800 mL baffled Fernbach flask with tap water on a rotaryshaker at 150 rpm. After 3 hours the contents of the flask is passedthrough a sequential series of different sized perforated plates withopenings of 12.5 mm, 6 mm, 3 mm, and 1.5 mm. Material retained on eachplate is recovered, dried at 40° C., and weighed. The percent ofmaterial retained is calculated based on the initial weight of the wetwipe. The overall loss of the wet wipe is also calculated.

Basis Weight Test Method

Basis weight of a fibrous structure and/or wet wipe sample is measuredby selecting twelve (12) usable units (also referred to as sheets) ofthe fibrous structure and/or wet wipe and making two stacks of six (6)usable units each. Perforation, if any, must be aligned on the same sidewhen stacking the usable units. A precision cutter is used to cut eachstack into exactly 8.89 cm×8.89 cm (3.5 in.×3.5 in.) squares. The twostacks of cut squares are combined to make a basis weight pad of twelve(12) squares thick. The basis weight pad is then weighed on a toploading balance with a minimum resolution of 0.01 g. The top loadingbalance must be protected from air drafts and other disturbances using adraft shield. Weights are recorded when the readings on the top loadingbalance become constant. The Basis Weight is calculated as follows:

${{Basis}\mspace{14mu} {Weight}\mspace{14mu} ( {{lbs}\text{/}3000\mspace{14mu} {ft}^{2}} )} = \frac{{Weight}\mspace{14mu} {of}\mspace{14mu} {basis}\mspace{14mu} {weight}\mspace{14mu} {pad}\mspace{14mu} (g) \times 3000\mspace{14mu} {ft}^{2}}{\begin{matrix}{453.6\mspace{14mu} g\text{/}{lbs} \times 12\mspace{14mu} ( {{usable}\mspace{14mu} {units}} ) \times} \\\lbrack {12.25\mspace{14mu} {in}^{2}\mspace{14mu} {( {{Area}\mspace{14mu} {of}\mspace{14mu} {basis}\mspace{14mu} {weight}\mspace{14mu} {pad}} )/144}\mspace{14mu} {in}^{2}} \rbrack\end{matrix}}$${{Basis}\mspace{14mu} {Weight}\mspace{14mu} ( {g\text{/}m^{2}} )} = \frac{{Weight}\mspace{14mu} {of}\mspace{14mu} {basis}\mspace{14mu} {weight}\mspace{14mu} {pad}\mspace{14mu} (g) \times 10\text{,}000\mspace{14mu} {cm}^{2}\text{/}m^{2}}{\begin{matrix}{79.0321\mspace{14mu} {cm}^{2}\mspace{14mu} ( {{Area}\mspace{14mu} {of}\mspace{14mu} {basis}\mspace{14mu} {weight}\mspace{14mu} {pad}} ) \times} \\{12\mspace{14mu} ( {{usable}\mspace{14mu} {units}} )}\end{matrix}}$

Caliper Test Method

To measure the caliper (thickness) of a wet wipe, the followingprocedure is used. Identify a minimum of 5 different locations on thewet wipe to measure the caliper. Cut the 5 or more portions (replicates)in a dimension greater than the foot of the Caliper Tester (Ono SokkiGS—503 Linear Gauge Sensor with an Ono Sokki DG3610 display orequivalent. May be obtained from Measure-All, Inc. 447 Nilles Road,Fairfield, Ohio 45014). to contact the sample. When testing finished wetwipe product, open a package of wet wipes and randomly select 5 finishedwet wipe products and measure immediately in their normal wet state.Place package with remaining product in a resealable plastic bag andseal.

Before using the Caliper Tester, make sure that the pressure foot (astainless steel circular foot Area: 2500 mm²±50 mm² (56 mm Diameter) andFoot Pressure: 0.501 kPa±0.021) and anvil surfaces are clean, that thecalibration of the instrument has been done per the manufacturer'sinstruction manual, and that the instrument is mounted on a solid levelsurface free from noticeable vibration, for example a granite base withmounting arm (Chicago Dial Indicator Co. Part No. 608-12-1R orequivalent), which may be obtained from Measure-All, Inc. 447 NillesRoad, Fairfield, Ohio 45014. Calibration should include verification of0.501 kPa±0.021 (0.073 PSI±0.003) pressure with a balance, verificationthat the presser foot is level to the base ±0.05 mm, and readings ofsteel gauge blocks accurate to ±0.05 mm. Zero the thickness gauge asdescribed by the manufacturer.

With the Caliper Tester foot in the up-position, center the sampleportion underneath. Lower the foot with the handle at a rate ofapproximately 3 mm per second. After the foot contacts the sample, wait5 seconds and record the caliper (thickness) result for each sampleportion (replicate).

1) Calculate the Mean for replicates used for measured sample.

2) Report Thickness in mm to the nearest 0.01 mm.

Do not use sample portions cut with a die. Do not make thicknessreadings on creases resulting from folds. Do not make thickness readingson samples with obvious defects such as wrinkles, tears, and holes. Donot handle in areas to be measured. Do not test the same area of asample portion more than once.

Elongation, Tensile Strength, TEA and Modulus Test Methods

To test wet wipes, open a package of wet wipes and remove 8 wet wipes.Place the opened package of wet wipes in a resealable plastic bag andseal. Using a 50 mm wide by 500 mm long precision sample cutter(JDC-50M-12, Thwing-Albert Instrument Company 10960 Dutton RoadPhiladelphia, Pa.) cut 4 replicates of each sample in the MD and CDdirections to a length greater than 250 mm. If sample available does notallow for the greater than 250 mm length report the length as adeviation and set the instrument gage length accordingly (see InstrumentSettings). The sample should be gripped by at least 25 mm at each end.For finished product wipes, test samples immediately. Cut samples fortheir unfolded position whenever possible. The total wet tensilestrength of a wet wipe is measured by this procedure also.

a. Testing Apparatus

Tensile Tester to be used and settings are as follows:

-   -   Tensile Tester Constant Rate of Elongation (CRE) Tensile Tester,        capable of performing the test profile as described.

Recommended Thwing-Albert Instruments:

EJA Vantage (preferred), EJA, or Intelect II STD Tensile Testers fromThwing-Albert Instrument Company, 10960 Dutton Road Philadelphia, Pa.19154 USA (215) 637-0100.

Recommended MTS Instruments:

MTS Synergie 200/L, MTS Alliance RT/1 Tensile Testers from MTS, 1001Sheldon Drive, Cary, N.C. 27513, or equivalent. Refer to AnalyticalMethod GCAS 58007265 “Testing and Calibration of Instruments—The TensileTester”.

-   -   Tensile Tester Load Cell—Cell should be chosen such that the        normally measured force is between 20% and 95% of the range in        use. Obtain from Tensile Tester Manufacturer.    -   Calibration Weights—Refer to Tensile Tester Manufacturer.    -   Tensile Tester Grips Flat face, air operated, at least 50 mm        wide purchased via the manufacturer of the tensile tester.        b. Instrument Settings

-   1. For MTS Instruments set the tensile tester to the following    parameters:

-   (For Thwing-Albert see Section 2 under “Instrument Settings” for all    others instruments check with the manufacturer for equivalent    instrument/software set up.)

Test Speed . . . 100 mm/min+2 mm/min

Gauge Length . . . 200 mm most preferred (EDANA)—or 50 mm acceptable ifsample size requires a shorter gauge length, as long as such deviationis reported.

Slack Compensation . . . A) 0.10N most preferred B) Non-use of slackcompensation is acceptable only on instruments that do not have slackcompensation functionality—such deviation must be reported.

Pre-test Path (no data) . . . None

Test path (data collected) . . . “Go Forever Until Break”

Post-test Path (no data) . . . None

Break Detection . . . 95% drop from Peak

Break Threshold . . . 0.25N (break detection inactive until this forceis reached)

Data Acquisition Rate . . . 100 Hz

Measured Variables . . . Tensile Strength (Peak Force) and Load at 5%Elongation—reported in Newtons to 1 decimal place (i.e. 33.5).Additionally, report % Elongation at Peak % of adjusted gauge length to2 decimal places (i.e. 10.44%).

-   2. For Thwing-Albert Instruments with APS Software set the tensile    tester to the following parameters:-   Test Units—Elongation Units . . . mms-   Test Units—Curve Units . . . load/elongation %-   Test Units—Load Units . . . N-   Set Mode . . . Tension-   Test Over . . . Fail-   Set Range . . . 100%-   At Test End . . . Return-   Speeds—Pre-Test . . . 100.000 mms/min-   Speeds—At Start of Test . . . 100.000 mms/min-   Speeds—For a distance of . . . 1.000 mms-   Speeds—Then crosshead will travel at . . . 100.000 mms/min-   Speeds—Return . . . 1015.998 mms/min-   Sample Rate . . . 100 readings/sec-   Collision . . . Yes-   Gauge Length . . . 200 mm most preferred (EDANA)—50 mm acceptable if    sample size requires a shorter gauge length, as long as such    deviation is reported.-   Adj. GL . . . Adjusted-   Break Sensitivity . . . 2 N-   Pre-tension . . . 0.10 N-   Load Divider . . . 1-   Sample shape/size—Sample Shape . . . Rectangular-   Sample shape/size—Width . . . 50.000 mms-   Sample shape/size—Thickness . . . 10.000 mms-   Tag Results—El Trp Load:-   Load Units . . . N-   Add'l Parameters . . . 5.000%-   Tag Results—Tangent Modulus:-   Elong. Units . . . cm-   Load Units . . . grams-   Add'l Parameters . . . Load-   Load Trap gms . . . 75.000-   Measured Variables . . . Tensile Strength (Peak Force) and Load at    5% Elongation—reported in Newtons to 1 decimal place (i.e. 33.5).    Additionally, report % Elongation at Peak in % of adjusted gauge    length to 2 decimal places (i.e. 10.44%). Also in this test set up    Tangent Modulus @ 15 gm/cm is shown and may be additionally reported    if desired.

Check tensile tester calibration according to manufacturer'sinstructions. Check the load cell for zero reading and adjust ifnecessary. Clamp the sample in the grips of the tensile tester, mountingthe sample without any pretension (<0.05N). Begin the test by depressingthe start (i.e., test) button. When the test is complete, record thevalues, remove the tested sample from the grips and discard. Check theload cell for zero reading and repeat this procedure until all samplesare tested. Discard the results of any sample where the sample 1) slipsduring the test, 2) the break occurs in or at either grip or 3) whereany break reaches the grips.

c. Calculations

-   Record each of the following variables for each replicate:    -   Peak Load (in Newtons to the nearest 0.1).    -   Load at 5% Elongation (in Newtons to the nearest 0.1).—this        quantity is not specifically mentioned by EDANA 20.2-89, but it        a useful measure for process-development.    -   % Elongation at Peak—EDANA 20.2-89 states to measure %        Elongation at break, but “break” is not clearly defined by EDANA        (i.e. 50% drop from peak, 75% drop, 95% drop?).        Additionally, these samples often fail in different ways leading        to highly variable elongation data (if “break” is defined as        complete failure of the sample). This method measures %        Elongation at Peak.Option for Thwing-Albert Instruments:    -   Tangent Modulus @ 15 g/cm.

Any of the units can be converted to other units for example g/in fortensile by appropriate conversion factors known in the art.

d. Reporting Results

Report mean and standard deviation for each measured quantity expressedin N (Newtons) and report any deviation (i.e. shorter gauge length dueto short sample length, no slack compensation available, etc). Reportthe number of replicates used for testing.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

Every document cited herein, including any cross referenced or relatedpatent or application, is hereby incorporated herein by reference in itsentirety unless expressly excluded or otherwise limited. The citation ofany document is not an admission that it is prior art with respect toany invention disclosed or claimed herein or that it alone, or in anycombination with any other reference or references, teaches, suggests ordiscloses any such invention. Further, to the extent that any meaning ordefinition of a term in this document conflicts with any meaning ordefinition of the same term in a document incorporated by reference, themeaning or definition assigned to that term in this document shallgovern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

1. A wet wipe comprising a fibrous structure comprising a liquidcomposition, wherein the liquid composition after extraction from thefibrous structure exhibits a pH of less than 4.55 as measured accordingto the pH Test Method described herein.
 2. The wet wipe according toclaim 1 wherein the fibrous structure comprises pulp fibers.
 3. The wetwipe according to claim 2 wherein the fibrous structure comprisesgreater than 85% by weight on dry basis of pulp fibers.
 4. The wet wipeaccording to claim 3 wherein the fibrous structure comprises about 100%by weight on a dry basis of pulp fibers.
 5. The wet wipe according toclaim 2 wherein the pulp fibers comprise fibers selected from the groupconsisting of: softwood fibers, hardwood fibers, and mixtures thereof.6. The wet wipe according to claim 5 wherein the pulp fibers comprise100% by weight on a dry basis of softwood fibers.
 7. The wet wipeaccording to claim 5 wherein the pulp fibers comprise greater than 50%by weight on a dry basis of softwood fibers and less than 50% by weighton a dry basis of hardwood fibers.
 8. The wet wipe according to claim 5wherein the softwood fibers are selected from the group consisting of:Northern Softwood Kraft fibers, Southern Softwood Kraft fibers, andmixtures thereof.
 9. The wet wipe according to claim 5 wherein thehardwood fibers comprise tropical hardwood fibers.
 10. The wet wipeaccording to claim 5 wherein the hardwood fibers are selected from thegroup consisting of: Acacia, Eucalyptus, Maple, Oak, Aspen, Birch,Cottonwood, Alder, Ash, Cherry, Elm, Hickory, Poplar, Gum, Walnut,Locust, Sycamore, Beech, Catalpa, Sassafras, Gmelina, Albizia,Anthocephalus, and Magnolia fibers, and mixtures thereof.
 11. The wetwipe according to claim 1 wherein the fibrous structure is a wet-laidfibrous structure.
 12. A wet wipe comprising a fibrous structurecomprising a liquid composition, wherein the fibrous structure comprisesa temporary wet strength agent.
 13. The wet wipe according to claim 12wherein the fibrous structure comprises pulp fibers.
 14. The wet wipeaccording to claim 12 wherein the fibrous structure is void of anypolymeric binder.
 15. The wet wipe according to claim 12 wherein thefibrous structure is a wet-laid fibrous structure.
 16. A wet wipecomprising a fibrous structure comprising a surface comprising a surfacepattern imparted to the fibrous structure during the fibrous structuremaking process and a liquid composition.
 17. The wet wipe according toclaim 16 wherein the fibrous structure is a wet-laid fibrous structure.18. The wet wipe according to claim 16 wherein the surface patterncomprises regions of different densities.
 19. The wet wipe according toclaim 18 wherein the surface pattern comprises discrete, high densityregions and a continuous or substantially continuous network of a lowdensity region surrounding the discrete, high density regions.
 20. Thewet wipe according to claim 16 wherein the surface pattern comprises anon-random, repeating pattern.